Band-saw mill



No. (9,490. Patented Feb. [4, I899. A. G. LAWRENCE.

BAND SAW MILL.-

(Application filed. m. 24, 1597. .(No Modal.) 2 Sheets-Sheet I.

Q M NT R his elf/always THE mums pzrzns co. PHOTO LIYHO., WASHINGTON, n, c.

N0. 6l9,490- Patented Feb. l4, I899.

A. a. L-AWRENEE.

BAND SAW MILL.

(Appliation filed Mar. 24, 1897.) {No Model.) 2 Sheets-Sheet 2.

fiz/T enior;

flae/berf 0. Lawrence.

Q OWJL V ail-0 r'neyd' PATENT ADELBERT e. LAWRENCE,

OF MOTLEY, MINNESOTA.

BAND-SAW MILL.

SPECIFICATION forming part of Letters Patent No. 619,490, dated February 14, 1899.

Application filed March 24, l 8 9 7.

To all whom it may concern:

Be it known that I, ADELBERT G. LAW- RENCE, of Motley, county of Morrison, State of Minnesota, have invented certain new and useful Improvements in Band-Saw Mills, of which the following is a specification.

Myinvention relates to band-saw mills, and particularly to means for controlling and driving the band-saw in its passage from one wheel to the other; and, further, the invention relates particularly to means for controlling the position, the tension, and other conditions of the saw-blade without the use of rigid or fixed guides.

The objects of the invention are to provide means for controlling the saw-blade under all conditions, to maintain a uniform tension thereon, to hold the saw-blade upon the carrying-wheels with equal pressure at all points, to prevent the natural throw or pitch of the saw from the carrying wheel or-wheels due to centrifugal force, and thereby minimize the vibration of the saw, all to the end thatthe saw may be operated at a higher speed, the danger connected with its operation greatly lessened, the power required for running the saw decreased in proportion to the work accomplished, and to the end that the output of the machine will be greatly increased through an increase in the speed of the saw, that the lumber may be sawed with a smaller kerf, thereby saving stock, and that the life of the machine, and particularly of the sawblade, may be greatly increased.

A further and particular object is to so modify the construction and operation of a band-saw mill that men of ordinary skill only and fewer skilled men will be required to run the same.

Heretofore while band-saws have been preferred to circular saws, particularly in the smaller lumber-mills, owing to the saving in the cut of kerf and the supposed consequent economy, of late the question of economy has come into dispute, owing to the fact that while in operation the band-saw vibrates to such an extent as to make a very rough surface upon the boards, so that nearly all that is gained in the kerf is lost in resurfacing the boards. To obviate this difficulty and to allow the mill to be worked at a much greater speed, so that the output of the band-saw Serial No. 628,931. (No model.)

mill will more nearly approach that of a ciroular saw mill, I provide a running guide or guides for the saw-blade. My invention consists in this guide or controller, in the particular construction and arrangement thereof, and in detail constructions, all as hereinafter described, and particularly pointed out in the claims.

The invention will be more readily understood by reference to the accompanying drawings, in which Figure 1 is an elevation of a band-saw mill embodying my invention. Fig. 2 is a sectional view on the line 00 w of Fig. 3. Fig. 3 is an end View of the upper portion of the mill. Fig. 4 is a detail view showing a guide-roller which is arranged at the back of the saw-blade. Fig. 5 is a sectional view of the rim of the carrying-wheel, the saw-blade, and the traveling guide or belt. Fig. 6 is a sectional view showing a modified construction of the belt.

As shown in the drawings, 2 represents the base of the mill, which base is provided with the hanger 3 for the shaft i of the lower carrying and power wheel 5. The base is pro vided with the upwardly-projecting arms or standards 6, in which the vertically-movable yoke-legs 7 are arranged. These yoke-legs carry the boxes 8 for the shaft 9 of the upper carrying-wheel 10.

11 represents the band-saw, which is arranged upon the two carrying-wheels and is driven by the lower wheel. The band-saw is placed under tension by a spring or weight mechanism (not shown) connected with the two vertically-movable yoke-legs 7.

12 represents the fixed guide,-which is employed to hold the saw beneath the cut.

13 represents a frame mounted upon the shaft 9, but stationary with the box 8 of said shaft. From the lower part of the frame extends an arm 14, which has an adjustable outer section 15, in which is secured the studshaft 16 of the pulley 17. To the upper'part of the frame 13 is hinged or pivoted the lower end of the arm or rod 18, which is also provided with an adjustable outer section 19, which carries the stud-shaft 20 of the pulley 21. The arm-sections 15 and 19 are provided with slots 22, which admit of a nice adjust ment and alinement of the pulleyshafts. The pulleys 17 and 21 carry the belt or traveling guide 23, and the upper pulley is provided with a flange 2t to prevent longitudinal movement of the belt upon the pulley or with respect to the saw-blade with which the inner leg of the belt 23 engages and conforms. The lower arm is preferably provided with a backing or limiting roller 25, which engages the rear edge of the saw and prevents the same from being forced off of the carryingwheels by the pressure of the log on the moving carriage. The pivot-point of the arm 18 is eccentric with respect to the shaft 9, in order that the pulley 21 maybe swung away from the wheel 10 when desired. The pulleys 21 and 17 are held upon and the belt 23 tightened by means of the toggle-lever 26, arranged between said arms or bars 14 and 18. A uniform tension is applied to the belt by means of the rod 28, the collar 29, and the spring 30, the collar being held by the lever 31 and adjustable thereby, a suitable ratchet or catch being provided for the lever. The bar 18 has a wide or long bearing upon the frame 13, and in order to accurately aline the two pulleys with the surface of the carrying-wheel 10 and of the saw I preferably make the frame 13 in two main depending parts, which are connected by adjustable rods or ties 32, whereby the arms 18 and 19 may be moved toward or from the side of the wheel 10. It is desirable to relieve the universaljoint bearing 8 from the tension and weight of said arms, while permitting the movement of said parts with said shaft and the wheel 10, which is required owing to the frequent tilting of the upper carrying-wheel. For this purpose I provide the lever 33, upon the rear end of which is an adjustable weight 34. The lever engages the bar 14 close at its outer end and just inside of the saw-blade. It is fulcrumed in the end 3a of the adjustable bracket 35. As band-saws are of different lengths and the upper carrying wheel is dropped or raised, according to the length of each band-saw placed on it, it is necessary, therefore, that the fulcrum of the counterbalance-lever should be raised or lowered accordin g1 y. As a means to adjust this bracket I have shown a simple jack-screw 36, provided on the side of the base; but parts already in use for the usual upper saw-guides in most band-sawmills maybe used for this purpose. It is necessary that the bracket be adjustable in order to raise the lever 33 to a point where it will nicely counterbalance the weight of the arms, pulleys, and belt. The bracket 35 is preferably provided with upwardly-extend,- ing arms or forks 37, which embrace the sides of the arm 14 and help to hold the same in position.

The arrangements of the belts 23 upon the downward-going sides of the saw prevents the natural centrifugal throw of the saw from the surface of the wheels and holds the saw in exact tangential line with the two wheels, preventing all vibration and doing so without a waste of power. Such a waste of power vide a similar belt or traveling guide 38, making the same longer, however, as it is desirable to engage the blade at the first point where it would naturally leave the power-wheel owing to centrifugal action. The lower wheel or pulley 39 and the idler-pulley 40, which engages with the outside leg of the belt 38, have fixed bearings, while the upper pulley 41 is provided in a vertically-adj ustable hearing, in connection with which a suitable tension mechanism is arranged. This part of the device may comprise a lever 42 and weight 413. With the exception of the pulley which is at the point where the belt leaves the saw all pulleys which are used to carry a traveling guide or belt are flanged to hold the belt firmly in position. To prevent the sawdust passing between the belt 38 and the band-saw blade, I arrange a fan or brush 4C4: beneath the lower carrying-wheel and drive the same by a straight belt from a large pulley on the shaft 4. The fan or brush 44 does not catch the main body or stream of sawdust which follows the saw, but will brush or blow the dust and gum from the outer surface of the saw-blade. This portion of my invention would be applicable to the common bandsaw mill with advantage, as it would prevent much of the gumming of the parts.

A very slight change in either the inclination of the upper carrying-wheel or the tension of the saw will cause the saw to run off the carrying-wheel or result in the breaking of the saw. To obviate the difficulty in a great measure, it is common to hammer the middle portion of the band-saw blade, so that only the edges of the same engage the surfaces of the carrying-wheels. The surface exposed for the transmission of power is therefore small, and this, taken in connection with the comparatively light tension which the saw will stand, owing to the intense vibration thereof while running, as ordinarily used, limits the possibilities of band-saw mills when compared with circular saws. To increase the pressure of the edges or edge surfaces of the saw-blades upon the carrying-wheel and absolutely prevent the vibration of the sawblade upon the carrying-wheel, the belts 23 and 38 are made with raised edges or wide ribs, as shown in Figs. 5 and (3. The middle of the belt does little more than contact with the middle portion of the blade. the belt 23 or the belt 38 inelastic in these essential parts-namely, the higher edges or rib portions 44-said parts are inlaid with steel wires or bands or warp 45.46, as indicated in Figs. 5 and 6, the same being endless hoops or rings of exactly the same length and tensile strength. To minimize the longitudinal play or movement of the wires or bands in the body of the belt, the same are placed as close as possible to the inner sur- To render.

face 47 of the belt, the wires or bands bending easily around the pulleys that carry the belt. The belt may be made of cloth, rubher, or leather, after any of the common modes of belt manufacture. V

The use and operation of my invention are as follows: After the saw is placed upon the carrying-wheels and the tension thereon adj usted the belt 23 is placed upon the flanged pulley and upon the lower belt-pulley. The lever 31 is then thrown to straighten the tog gle-lever 26, and thereby place belt 23 under tension. Meantime both belt-pulleys are adjusted exactly with relation to the carryingwheel and the band-sawthat is, the upper pulley is adjusted so that its flanges just escape the saw-blade, while the lower pulley is moved so that the lower part of 23 will be exactly parallel with a straight line drawn between the peripheries of the upper and lower carrying-wheels and will contact with the same. With the proper tension upon the belt, and the same is true of the lower belt or traveling guide 28, the raised edges of the belt will press firmly against the edge portions of the band-saw blade, holding the same snugly upon the wheel and compelling the saw to cling to the carrying-wheel, and, further, to immediately assume a perpendicular position after leaving the periphery of the carryingwheel. Thus all vibration is prevented, as the saw will not move inwardly and cannot move outwardly owing to the traveling guide.

If required, a small idler-pulley or roller 25 may be arranged to engage the inside of the saw-blade opposite the wheel or the pulley 17. The nicest possible adjustments may be had by means of the adjustable rods of the frame, which carries the arms for the upper belt, aided by the exact counterbalance obtained by means of the scale-lever 33. By means of my appliances the belt'is kept at a uniform tension both in regard to its length, the length of opposite edges of the saw-blade, and the width of the saw-blade, with the result that with the vibration minimized and practically avoided a much greater tension may be applied to the saw-blade, and it may be rotated with greater speed owing to the increased frictional engagement with the carrying-wheels, and yet with perfect safety, inasmuch as the engagement of the traveling belts ori guides and the even tension upon the same prevent backward and forward movement of the bandsaw upon the two carrying-wheels. The element of safety in band-saws is a very important one, as many accidents have occurred from the breaking of the bands. ther true that owing to the uniform tension maintained throughout the band-saw and the perfect control of the same without the employment of a rigid upper guide the saws willvlast for a much greater time, need not be hammered so often, and may be used even after they are considerably worn away in width.

Having thus described my invention, I

It is fur-v claim as new and desire'to secure by Letters Patent- 1. In a band-saw mill, the combination, of the carrying-wheels, one adapted to be driven and to drive the band-saw, and the other being an idler to carry the band-saw, with normally-fixed pulleys arranged opposite the periphery of one of said wheels, one of said pulleys being near the periphery of said wheel, and the other having its periphery, adjacent to said wheel, substantially included in atangent drawn between the two carrying-wheels, and a traveling guide or belt arranged upon said normally-fixed pulleys upon the delivery side of said wheel and pressing the saw upon the adjacent carrying-wheel, whereby the saw is held upon said carrying-wheel, and, when leaving the same, is held in a true tangent between the two carrying-wheels, substantially as described.

2. In aband-saw mill, the combination,with the carrying-wheel, of the fixed pulleys and the belt arranged upon said pulleys, and the means for exerting a tension upon said belt to press the same against the periphery of said wheel or the saw-blade thereon, and one of said pulleys being so placed as to deliver the saw in an exact tangential position with respect to thetwo driving-wheels, whereby vibration is prevented, substantially as described.

3. In a band-saw mill, the combination, of the carrying-wheels, one adapted to be driven and to drive the band-saw, and the other being an idler to carry the band-saw, with normally-fixed pulleys arranged opposite the periphery of one of said wheels, one of said pulleys being near the periphery of said wheel, and the other havingits periphery, adjacent to said wheel, substantially included in a tangent drawn between the two carrying-wheels, said pulleys being adjustable with relation to said wheel and one another, and a travel ing guide or belt arranged upon said pulleys upon the delivery side of said wheel and pressin g the saw upon the adjacent carrying-wheel, whereby the saw is held upon said carryingwheel, and when leaving the same, is held in true position between the two carryin g-wheels, substantially as described.

4. The combination, in a band-saw mill, of the carrying-wheel, the shaft thereof, the bearing for said shaft, a fixed frame extending from said bearing to move therewith when the wheel is tilted, pulleys carried by said frame opposite the face or periphery of said wheel, a belt upon said pulleys, which belt contacts with a considerable area or extent of the periphery of said wheel or the saw thereon, and the means for increasing or decreasing the tension of said belt, substantially as described.

5. In aband-saw mill, the combination,with the carrying-wheel, of the pulleys arranged opposite the same and supported upon a frame which is movable with said wheel when the same is tilted, and a belt or traveling guide carried by said pulleys and to contact with said wheel and deliver the saw therefrom in an exact position, substantially as described. 1

6. The combination in a band-saw mill, of the carrying-wheels with a fixed flanged pulley arranged in close proximity to the periphery of the lower carrying-wheel, and a movable or adjustable pulley provided opposite the points where the saw leaves the lower wheel, as and for the purpose specified.

7 In aband-saw mill, the combination,with the carrying-wheels and their shafts, of a frame comprising the bars or arms supported by the parts which carry the shaft of the upper wheel, the upper bar or arm being hinged eccentrically with respect to the shaft of the upper wheel, pulleys carried by said arms, and a traveling guide or belt arranged upon said pulleys, substantially as described.

8. In a band-saw mill, the combination,with the upper carrying-wheel and its shaft, of a frame supported by the parts which carry said shaft, arms extending from said frame to points outside the periphery of said carryingwheel, pulleys carried upon the ends of said arms or bars, a belt arranged thereon to contact with the saw upon the wheel, and means for supporting said arms to increase the tension upon said belt,substantially as described.

9. Inaband-saw mill, the co1nbination,with the upper carrying-wheel and its shaft, of a frame supported by the parts which carry said shaft, arms extending from said frame to points outside the periphery of said carryingwheel, pulleys carried upon the ends of said arms or bars, a belt arranged thereon to cou- 1 tact with the saw upon the wheel, means for supporting said arms to maintain the tension upon said belt, and further means for maintainin g a uniform pressure between said arms while permitting the same to yield, substantially as described.

10. In a band-saw mill, the combination, with the carrying-wheels, of a frame to carry pulleys in close proximity to the upper bandwheel, a traveling guide or belt arranged upon said pulleys, said pulleys being adjustable with respect to one another, and a weighted lever or spring to support or carrypart or all of the weight of said frame and said pulleys, substantially as described.

11. In a band-saw mill, the combination, with the upper carrying-wheel, of a frame constructed substantially about the axis of said carrying-wheel and supported from the parts which carry said wheel, pulleys arranged upon said frame, a traveling guide or belt on said pulleys, and adjustable means to aid in the support of said frame, substantially as described.

12 In a band-saw, the combination, with the upper carrying-wheel and the base, of the frame carried by said base and adapted to move with the upper wheel when itis tilted, pulleys carried by said frame, a belt thereon, a lever engaging said frame near its outer or free end, and an. adjustable fulcrum upon said base for said lever, substantially as described.

13. In a band-saw mill, the combination, with the upper wheel, the shaft and the bearings therefor, of a frame comprising upper and lower bars, said upper bar being movable, pulleys carried by said arms and adjustable toward and from said wheel, a belt upon said pulleys, and means for placing said belt under tension to engage the same with the saw upon the wheel, as and for the purpose specified.

14. In a band-saw mill, the combination, with the upper and lower carrying-wheel and the base, whereby the upper wheel is supported and whereon said upper wheel is mov able, a frame carried by the movable supports for said upper wheel, said frame being adjustable in vertical and horizontal planes, pulleys carried by said frame in proximity to .the upper wheel, and a belt arranged upon said pulleys, as and for the purpose specified.

15. The combination, in a band-saw mill, .of the upper and lower wheels to carry the band-saw, of the horizontally-arranged arm or support, the outer and inner pulleys car- .ried thereby and between which the saw op- .erates, an upper pulley suitably supported, a traveling guide or belt arranged upon said upper pulley and said outer pulley and upon ,the delivery side of the wheel to press against ,the saw and at its lower end operating substantially at a tangent to the upper carryingwheel and pressingthe saw toward said inner pulley, substantially as described.

16. The combination, with the upper and lower carrying-wheels, of a band-saw mill, and means for driving same, of a traveling guide or belt arranged beneath and back of the lower carrying-wheel, pulleys over which ,said belt operates to hold said saw upon said lower wheel and at a tangent with the rear side or face thereof, and a rotating brush or like device arranged opposite the lower forward side or face of said lower carrying-wheel to clear the saw and-prevent sawdust and chips from passing between the saw and said traveling belt or guide, substantially as described. 17. A traveling guide for band-saw mills, comprising an endless belt having raised edges and a concave middle part, the elevation of the middle part above said edges corresponding to the crown or concave of a bandsaw for lumber-mills, substantially as described. 18. The combination, with the band-saw and the carrying or driving wheel, of the pulleys arranged opposite the delivery side of said wheel, and the endless belt or traveling guide arranged upon said pulleys and having raised edges bearing upon the edge portions of the saw upon said wheel, substantially as described. 19. The travelingguide forband-saws,co1nprising an endless belt having an endless metallic warp in its edge portions to prevent the stretching of said edge portions, the edges of said belt being raised, in combination, with the band-saw carrying or driving Wheel Whereto said raised edges are presented, and the guide or belt carrying pulleys whereto the smooth surface of said endless belt is presented, substantially as described.

In testimony whereof I have hereunto set my hand this 15th day of March, A. D. 1897.

ADELBERT G. LAWRENCE.

In presence of- O. G. HAWLEY, M. E. GOOLEY. 

